DESCRIPTION (provided by investigator): Acute Lung Injury (ALI) is a syndrome characterized by acute, diffuse pulmonary capillary leak resulting in hypoxic respiratory failure. It is caused by a diverse group of pulmonary (e.g. aspiration) and non-pulmonary (e.g. sepsis) factors. ALI imposes a significant public health burden with an incidence that is much higher than previously recognized (86 per 100,000 person years) and a total number of deaths similar to breast cancer or HIV infection. Due to advances in medical care, the mortality rate for ALI has decreased from ~70 per cent to ~40 per cent. Patients who previously may have died now survive ALI;however, their recovery is often long and complicated. Research studying the long-term outcomes of these ALI survivors has become increasingly important. Recent studies have demonstrated important and persistent morbidity in ALI survivors. However, these studies were limited in sample size and duration of follow-up, and provided little information on the effect of intensive care unit (ICU) therapies on long-term outcomes. Consequently, our goal is to learn how existing ICU therapies can be used to minimize long-term physical and mental health morbidities and improve patients'functional status and quality of life after ALI. We propose to extend our existing cohort study, which follows patients for 2 years after ALI, to allow 5- year follow-up. In this proposed research, we will study new relationships of ICU therapies with patients'long term outcomes. Specifically, we will study the epidemiology of muscle weakness, and symptoms of anxiety, depression and post-traumatic stress disorder at up to 5 years after ALI, and the association of these sequelae with limitations in patients'physical function and quality of life [Aims 1a and 2a]. We will then determine the association of nutrition and corticosteroids in the ICU with long-term muscle weakness [Aim 1b]. We also will determine the association of delirium and corticosteroids in the ICU with long-term symptoms of post-traumatic stress disorder [Aim 2b]. Through this research, we will understand how existing ICU therapies and exposures can improve long-term physical and mental health after acute lung injury. PUBLIC HEALTH RELEVANCE Acute lung injury (ALI) usually requires artificial life support in the intensive care unit (ICU) and is common, costly and associated with significant long-term muscle weakness and symptoms of anxiety, depression and post-traumatic stress disorder in surviving patients. This research will provide new knowledge regarding the frequency of these morbidities, their consequences for patients, and how nutrition, corticosteroids and delirium in the ICU may reduce or exacerbate these morbidities up to 5 years after ALI.